Nacelle mounted latching system

ABSTRACT

A nacelle for a gas turbine engine includes a bifurcation, an outer diameter cowl and a first latch system. The outer diameter cowl extends from the bifurcation and the first latch system is mounted on the outer diameter cowl. The first latch system is spaced along the outer diameter cowl from the bifurcation.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of PCT applicationPCT/US2014/025335, filed Mar. 13, 2014, for “Nacelle Mounted LatchingSystem” by Nigel David Sawyers-Abbott and Joseph P. Foster, and U.S.Provisional Application No. 61/788,338, filed Mar. 15, 2013, for“Nacelle Mounted Latching System” by Nigel David Sawyers-Abbott andJoseph P. Foster.

BACKGROUND

This disclosure relates to gas turbine engines, and in particular, to asystem for latching a gas turbine engine nacelle.

Gas turbine engines typically include a nacelle surrounding an enginecore. Portions of the nacelle can use a latch system to couple portionsof the nacelle to one another and to latch to the engine core itself. Insome embodiments, a fan case, which surrounds the fan, can be latched tothe nacelle. These latches keep the nacelle and fan case from separatingdue to load events such as a burst Environmental Control System (ECS)duct. The latch system needs to be released to open the nacelle foron-the-ground maintenance of the engine core.

To facilitate on-the-ground maintenance, nacelles are typically dividedalong split-lines into two cowl halves called doors. Current latchsystems typically latch together the two cowl halves along a bifurcationwith a split-line at the bottom dead center of the gas turbine engine.Although effective, the envelope in this area is limited due tomechanical, electrical, and other systems. Thus, it can be difficultwith current latch systems to run cables and position latches along thebifurcation. Additionally, with the advent of gas turbine engines thatemploy a lower fan pressure ratio during operation, it is desired tohave latch systems resist load events such as a burst EnvironmentalControl System (ECS) duct.

SUMMARY

A nacelle for a gas turbine engine includes a bifurcation, an outerdiameter cowl and a first latch system. The outer diameter cowl extendsfrom the bifurcation and the first latch system is mounted on the outerdiameter cowl. The first latch system is spaced along the outer diametercowl from the bifurcation.

A nacelle for a gas turbine engine includes a first door, a first latchsystem, a second door, and a second latch system. The first door has afirst outer diameter cowl connected to a first half of a lowerbifurcation. The first latch system is mounted on the first outerdiameter cowl and is spaced along the first outer diameter cowl from thelower bifurcation. The second door has a second outer diameter cowlconnected to a second half of the lower bifurcation. The second latchsystem is mounted on the second outer diameter cowl and is spaced alongthe second outer diameter cowl from the lower bifurcation.

A gas turbine engine includes a case and a nacelle. The nacelle islatched to the case and includes a bifurcation, an outer diameter cowland a first latch system. The outer diameter cowl extends from thebifurcation and the first latch system is mounted on the outer diametercowl. The first latch system is spaced along the outer diameter cowlfrom the bifurcation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section of a schematic gas turbine engine showing oneembodiment of a latching system connecting a nacelle to a fan case.

FIG. 2 is a semi-exploded perspective view of the nacelle with a door ofthe nacelle raised.

FIG. 3A is a perspective view of the nacelle employing the latchingsystem of FIG. 1.

FIG. 3B is a perspective view of the latching system of FIG. 3A inisolation including handles, cables, and latching mechanisms.

DETAILED DESCRIPTION

FIG. 1 illustrates one embodiment of gas turbine engine 10. Gas turbineengine 10 includes nacelle 12, fan case 14, core 16, intermediate case18, fan duct inner fixed structure 20, core compartment 22, compressedair duct 24, and latching system 26. Nacelle 20 includes thrust reverser28 with translating sleeve 30 and upper and lower bifurcations 32A and32B.

The construction and operational characteristics of gas turbine engine10 are known, and therefore, will not be described in great detail. Inthe embodiment shown in the FIGURES, gas turbine engine 10 is a highbypass ratio turbofan gas turbine engine but the invention is applicableto other types of gas turbine engines. As used herein, terms such as“front”, “forward”, “aft”, “rear”, “rearward” should be understood aspositional terms in reference to the direction of airflow A_(C) andA_(B) through gas turbine engine 10.

Nacelle 12 encloses fan case 14, which is disposed adjacent to core 16.Core 16 is a static structure generally comprised of severalsub-structures and is often referred to as the engine backbone. One ofsuch sub-structures is intermediate case 18, which encloses portions ofcompressor section of gas turbine engine 10 aft of fan case 14.

Inner fixed structure 20 of fan duct 34 surrounds the core 16 andprovides for core compartment 22. Various components may be provided inthe core compartment 22, such as fluid conduits, or compressed air duct24. Compressed air duct 24 is under high pressure and may supplycompressed air from low or high pressure compressor stage to higherpressure turbine stage for cooling. Compressed air from core 16 canadditionally be used in an ECS of an aircraft.

Only a portion of latching system 26 is shown in the cross-section ofFIG. 1, and connects nacelle 12 to fan case 14. In particular, latchingsystem 26 is positioned forward of or at intermediate case 18.Positioning latching system 26 at fan case 14 or at intermediate case 18allows latch system 26 to better resist load events such as a burst ECSduct, because the latches of latch system are disposed closer to core16.

Nacelle 12 portion aft of fan exit guide vanes includes thrust reverser28, fan duct inner fixed structure 20, and upper and lower bifurcations32A, 32B, collectively the structures form portions of fan duct 34. Inthe embodiment of FIG. 1, thrust reverser 28 is positioned along anouter diameter of nacelle 12 at an aft end thereof. Thrust reverser 28includes translating sleeve 30. Translating sleeve 30 is shown in aclosed position in FIG. 1.

Upper and lower bifurcations 32A and 32B extend generally radially inbypass flowpath of fan duct 34 between outer diameter of nacelle 12 andduct inner fixed structure 20. Upper and lower bifurcations 32A and 32Bare disposed in locations opposite one another relative to core 16 suchas along engine 10 top dead center and bottom dead center. Upper andlower bifurcations 32A and 32B accommodate wires, fluid conduits, enginemounting, or other components.

During operation, airflow is drawn into gas turbine engine 10 at the fansection. A portion of the airflow, comprising airflow A_(B), bypassescore 16 and passes through nacelle 12 along fan duct 34 and producesforward thrust. A second portion of the airflow, comprising airflowA_(C) enters and is pressurized in the compressor sections (low andhigh). Fuel is mixed with the pressurized air and combusted within acombustor. The combustion gases are discharged through the turbinesections (high and low), which extract energy therefrom for powering thecompressor sections and the fan section.

FIG. 2 shows a semi-exploded view of gas turbine engine 10 includingnacelle 12, fan case 14, core 16, intermediate case 18, inner fixedstructure 20, latching system 26, upper and lower bifurcations 32A and32B, and fan duct 34. Nacelle 12 includes doors 36A and 36B each withouter diameter cowl 38.

Nacelle 12 is split along fan duct inner fixed structure 20, upper andlower bifurcations 32A and 32B, and outer diameter cowl 36 into doors36A and 36B. Doors 36A and 36B pivot on hinges (not shown) to open andexpose core 16 and other components of gas turbine engine 10 forassembly, maintenance or engine removal and replacement. Doors 36A and36B are fastened or otherwise connected to pylon superstructure (notshown).

FIG. 2 shows door 36A drawn back away from core 16. Intermediate case 18is disposed at a forward portion of core 16 adjacent fan case 14. Doors36A and 36B are disposed to either side of core 24. In particular, innerfixed structure 20 of doors 36A and 36B surrounds core 16. As discussedpreviously, inner fixed structure 20 forms an inner diameter flow pathof fan duct 34. Similarly, outer diameter cowl 38 forms an outerdiameter flow path of fan duct 34. Inner fixed structure 20 is connectedto outer diameter cowl 38 by upper and lower bifurcations 32A and 32B.

Handle 40A of latching system 26 is disposed within outer diameter cowl38 near an aft end thereof. In particular, a portion of handle 40A isexposed along an outer surface of outer diameter cowl 38. The remainderof handle 40A and other components of latching system 26 are disposedwithin and extend forward through outer diameter cowl 38 towardintermediate case 18 and fan case 14.

As shown in FIG. 2, handle 40A is disposed circumferentially aboutnacelle 12 a distance away from upper and lower bifurcations 32A and 32Band split-line between doors 36A and 36B. Such a configuration avoidshaving to position handle 40A adjacent to or across the split-line, andadditionally avoids having to run parts of latching system 26 throughthe tight envelope of lower bifurcation 32B. Thus, disposing handle 40Aat a distance from lower bifurcation 32B frees up space within lowerbifurcation 32B for components such as wires and fluid conduits.

FIG. 3A shows a perspective view of nacelle 12 with various componentsremoved to illustrate one embodiment of latching system 26. FIG. 3Bshows components of latching system 26 in isolation. In FIG. 3A,components of doors 36A and 36B including inner fixed structure 20 andouter diameter flow surface of fan duct 34 (FIGS. 1 and 2) are removedto illustrate latching system 26, which includes handles 40A and 40B(not shown in FIG. 3A), linking members 42A, 42B, 42C, and 42D, andlatching mechanisms 44A, 44B, 44C, and 44D. Latching mechanisms 44A,44B, 44C, and 44D include brackets 46A, 46B, 46C, and 46D and pinlatches 48A, 48B, 48C, and 48D.

As shown in FIG. 3A, handles 40A and 40B are disposed within outerdiameter cowl 38 of each door 36A and 36B, respectively. In particular,handles 40A and 40B are disposed adjacent an aft end of nacelle 12 in anarea typically called aft area cowl 50. Thus, in the embodiment shown inFIG. 3A, handles 40A and 40B are mounted on aft area cowl 50 adjacentaft split-line 52. Aft area cowl 50 can include components such asthrust reverser 28 (FIG. 1). In some embodiments, handles 40A and 40Bare mounted on thrust reverser 28.

Handle 40A is connected to linking members 42A, 42B. Handle 40B isconnected to linking members 42C, 42D. Linking members 42A, 42B, 42C,and 42D extend forward from handles 40A and 40B internally through outerdiameter cowl 38 to latching mechanisms 44A, 44B, 44C, and 44D. Latchingmechanisms 44A, 44B, 44C, and 44D are adapted to interface with fan case14 (FIG. 1) and connect nacelle 12 to fan case 14. Brackets 46A, 46B,46C, and 46D are affixed to outer diameter cowl 38. Pin latches 48A,48B, 48C, and 48D are mounted within brackets 46A, 46B, 46C, and 46D,respectively, and can be actuated to engage with and disengage from lugsor similar mounting structure of fan case 14.

In FIG. 3A, a portion of handle 40A protrudes from door 36A and aportion of handle 40B is pivotable to protrudes from outer surface ofdoor 36B. Handles 40A and 40B are designed to open forward (into thedirection of airflow across nacelle 12 during operation). In theembodiment of FIGS. 3A and 3B, linking members 42A, 42B, 42C, and 42Dcomprise push-pull cables surrounded by sheaths. Thus, handles 40A and40B act as a lever and fulcrum to push and pull cables to actuate(insert or retract) pins of pin latches 48A, 48B, 48C, and 48D asdesired. Systems utilizing cables are described in further detail inU.S. Pat. Nos. 5,350,136 and 4,549,708, which are incorporated herein byreference. In other embodiments, the cables described can be substitutedfor rods, hydraulic, electronic, or other linkage components. Similarly,other mechanisms for connecting nacelle to fan case 14 can be utilizedin addition to or in alternative to pin latches 48A, 48B, 48C, and 48D.For example, hooks or other known methods of connection can be used inother embodiments. FIGS. 3A and 3B provide only one exemplaryembodiment, thus the number of handles 40A and 40B, linking members 42A,42B, 42C, and 42D, and latching mechanisms 44A, 44B, 44C, and 44D canchange from embodiment to embodiment.

As shown in FIG. 3A, handles 40A and 40B and linking members 42A, 42B,42C, and 42D are circumferentially spaced from upper and lowerbifurcations 32A and 32B. Such a configuration avoids having to positionhandle 40A adjacent to or across the split-line, and additionally avoidshaving to run parts of latching system 26 through the tight envelope oflower bifurcation 32B. Thus, disposing handle 40A at a distance fromlower bifurcation 32B frees up space within lower bifurcation 32B forcomponents such as wires and fluid conduits. Positioning latchingmechanisms 44A, 44B, 44C, and 44D at fan case 14 or at intermediate case18 allows latch system 26 to better resist load events such as a burstECS duct, because the latches of latch system are disposed closer tocore 16. Additionally, positioning handles 40A and 40B on each door 36Aand 36B allows doors 36A and 36B to be opened or latched independentlyof one another. Thus, only one door may be opened for assembly,maintenance or engine removal and replacement as desired.

While the invention has been described with reference to an exemplaryembodiment(s), it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment(s) disclosed, but that theinvention will include all embodiments falling within the scope of theappended claims.

Discussion of Possible Embodiments

The following are non-exclusive descriptions of possible embodiments ofthe present invention.

A nacelle for a gas turbine engine includes a bifurcation, an outerdiameter cowl and a first latch system. The outer diameter cowl extendsfrom the bifurcation and the first latch system is mounted on the outerdiameter cowl. The first latch system is spaced along the outer diametercowl from the bifurcation.

The nacelle of the preceding paragraph can optionally include,additionally and/or alternatively, any one or more of the followingfeatures, configurations and/or additional components:

a second latch system, wherein the outer diameter cowl is separated intofirst and second halves, and the first latch system is mounted on thefirst half and the second latch system is mounted to the second half;

-   -   the bifurcation comprises a lower bifurcation;    -   the first latch system includes a handle mounted within and        pivotable to protrude from the outer diameter cowl, one or more        linking members extending through the outer diameter cowl from        the handle, and one or more latching mechanisms disposed toward        a forward end of the outer diameter cowl and connected to the        one or more linking members;    -   the outer diameter cowl includes an aft area cowl and the handle        is mounted on the aft area cowl;    -   the handle opens in a forward direction relative to the outer        diameter cowl;    -   the handle is mounted to a thrust reverser of the outer diameter        cowl;    -   a fan case, the one or more latching mechanisms latch the        nacelle to the fan case;    -   the latching mechanism comprise pin latches that engage the fan        case; and    -   the one or more linking members comprise push-pull cables.

A nacelle for a gas turbine engine includes a first door, a first latchsystem, a second door, and a second latch system. The first door has afirst outer diameter cowl connected to a first half of a lowerbifurcation. The first latch system is mounted on the first outerdiameter cowl and is spaced along the first outer diameter cowl from thelower bifurcation. The second door has a second outer diameter cowlconnected to a second half of the lower bifurcation. The second latchsystem is mounted on the second outer diameter cowl and is spaced alongthe second outer diameter cowl from the lower bifurcation.

The nacelle of the preceding paragraph can optionally include,additionally and/or alternatively, any one or more of the followingfeatures, configurations and/or additional components:

-   -   the first latch system includes a handle mounted within and        pivotable to protrude from the first outer diameter cowl, one or        more linking members extending through the first outer diameter        cowl and connected to the handle, and one or more latching        mechanisms disposed toward a forward end of the first outer        diameter cowl and connected to the one or more linking members;    -   the first outer diameter cowl includes an aft area cowl and the        handle is mounted on the aft area cowl;    -   the handle opens in a forward direction relative to the first        outer diameter cowl;    -   the handle is mounted to a thrust reverser of the first outer        diameter cowl;    -   a fan case, the one or more latching mechanisms latch the        nacelle to the fan case;    -   the latching mechanism comprise pin latches that engage the fan        case; and    -   the one or more linking members comprise push-pull cables.

A gas turbine engine includes a case and a nacelle. The nacelle islatched to the case and includes a bifurcation, an outer diameter cowland a first latch system. The outer diameter cowl extends from thebifurcation and the first latch system is mounted on the outer diametercowl. The first latch system is spaced along the outer diameter cowlfrom the bifurcation.

The gas turbine engine of the preceding paragraph can optionallyinclude, additionally and/or alternatively, any one or more of thefollowing features, configurations and/or additional components:

-   -   the nacelle is latched to the case at a fan case.

While the invention has been described with reference to an exemplaryembodiment(s), it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment(s) disclosed, but that theinvention will include all embodiments falling within the scope of theappended claims.

1-20. (canceled)
 21. A nacelle for a gas turbine engine, the nacellecomprising: an upper bifurcation; and a lower bifurcation; an innerdiameter cowl extending between the upper and lower bifurcations; and afirst latch system mounted on the inner diameter cowl and spaced alongthe inner diameter cowl between the upper and lower bifurcations. 22.The nacelle of claim 21, further comprising a second latch system,wherein the inner diameter cowl is separated into first and secondhalves, and wherein the first latch system is mounted on the first halfand the second latch system is mounted to the second half.
 23. Thenacelle of claim 21, further comprising: an diameter outer cowl.
 24. Thenacelle of claim 21, wherein the first latch system includes: a handlemounted within and pivotal to protrude from the inner diameter cowl; oneor more linking members extending through the inner diameter cowl fromthe handles into the fan airflow; and one or more latching mechanismsdisposed toward a forward end of the inner diameter cowl and connectedto the one or more linking members.
 25. The nacelle of claim 24, whereinthe inner diameter cowl includes an aft core cowl and the handle ismounted on the aft core cowl.
 26. The nacelle of claim 24, wherein thehandle opens in a forward direction relative to the inner diameter cowl.27. The nacelle of claim 24, wherein the latching mechanism comprise pinlatches that engage the engine case.
 28. The nacelle of claim 24,wherein the one or more linking members comprise push-pull cables.
 29. Anacelle for a gas turbine engine, the nacelle comprising: a first doorhaving a first inner diameter cowl connected to a first half of a lowerbifurcation; a first latch system mounted on the first inner diametercowl and spaced along the first inner diameter cowl from the lowerbifurcation; a second door having a second inner diameter cowl connectedto a second half of between the upper and lower bifurcations; and asecond latch system mounted on the second inner diameter cowl and spacedalong the second inner diameter cowl between the upper and lowerbifurcations.
 30. The nacelle of claim 29, wherein the first latchsystem includes: a handle mounted within and pivotal to protrude fromthe first inner diameter cowl; one or more linking members extendingthrough the first inner diameter cowl and connected to the handle; andone or more latching mechanisms disposed toward a forward end of thefirst inner diameter cowl and connected to the one or more linkingmembers.
 31. The nacelle of claim 30, wherein the first inner diametercowl includes an aft core cowl and the handle is mounted on the aft corecowl.
 32. The nacelle of claim 30, wherein the handle opens in a forwarddirection relative to the first inner diameter cowl.
 33. The nacelle ofclaim 32, wherein the latching mechanism comprise pin latches thatengage the engine case.
 34. The nacelle of claim 30, wherein the one ormore linking members comprise push-pull cables.
 35. A gas turbine enginecomprising: a case; and a nacelle latched to the case, the nacellecomprising: an upper bifurcation; a lower bifurcation; an inner diametercowl extending between the upper and lower bifurcations; and a firstlatch system mounted on the inner diameter cowl and spaced along theinner diameter cowl between the upper and lower bifurcations.
 36. Thegas turbine engine of claim 35, wherein the bifurcation includes a firstdoor and a second door, and the first door is latched to the seconddoor.
 37. A gas turbine engine comprising: an engine core; a case; and anacelle latched to the case, the nacelle comprising: an inner diametercowl including a first bifurcation, the first bifurcation including afirst door and a second door that encompass at least a portion of theengine core; a first latch system mounted on the inner diameter cowl.38. The gas turbine engine of claim 37 wherein the first door and thesecond door are latched to the engine core.
 39. The gas turbine engineof claim 37 wherein the first latch system includes a structure thatlatches the first door to the second door.